A Metal Dual Work-Function Gate (MDWG) for the Continuous Scaling of DRAM Cell Transistors

The current dual work function gate (DWFG), utilizing Poly Si, which is applied as a standard in conventional DRAM products, is facing the issue of an exponential increase in word line (WL) resistance. For the continuous scale-down of DRAM cell transistors, we have demonstrated, for the first time, a metal dual work function gate (MDWG) by replacing n
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Poly Si with an Oxide/La (Lanthanum) /TiN structure in a fully integrated 1z-nm 16Gb DRAM. We confirmed a 40% improvement in retention time without an increase in WL resistance compared to the cell transistors with a single work function gate (SWFG).